Kidney cancer strikes more than 36,000 Americans every year, and kills over 12,600 adults and children. About half of new cases diagnosed in adults are localized, or limited to the kidney itself. Another 25 percent have advanced kidney cancer at diagnosis, and 25 percent will have regional kidney cancer.
Ultimately, about half of kidney cancer patients will experience metastases (tumor spread). The risk of metastasis is directly related to the size of the primary tumor.
In the 1980s, up to 80 percent of people had advanced kidney cancer when diagnosed. Today, thanks to advanced detection methods, only about 40 percent of patients have advanced kidney cancer at diagnosis.
Renal cell carcinoma (RCC) is the most common type of kidney cancer. Types of RCC include clear cell, papillary, chromophobe and collecting duct carcinomas. Clear cell carcinoma accounts for 80 percent of all RCC cases, and most treatments are focused on this type.
Due to the location of the kidneys, people often don't experience any symptoms until the tumor has grown quite large. The most common symptom is blood in the urine (hematuria), but the presence of blood doesn't necessarily mean it is cancer.
Other kidney cancer symptoms may include:
A lump or mass in the kidney area
Rapid weight loss
Lingering dull ache or pain in the side, abdomen or lower back
Feeling fatigued or in poor health
Having one or more of the symptoms listed above does not necessarily mean you have kidney cancer. However, it is important to discuss any symptoms with your doctor, since they may indicate other health problems.
There are several tests used to detect and stage kidney cancer:
Imaging studies such as a CT scan, ultrasound, MRI or intravenous pyelogram (IVP). CT scans are very useful for detecting kidney tumors. IVP, which involves injecting a dye that shows up on an X-ray as it travels through the urinary system, can be helpful in diagnosing kidney cancer. These imaging studies can also be used for disease staging to help oncologists determine the appropriate treatment.
Fine Needle Aspiration (FNA) involves the insertion of a long, thin needle into the kidney to take a tiny sample of tissue (biopsy) for examination under a microscope. FNA is generally used if other tests have failed to prove the presence of a tumor.
Surgery to treat kidney cancer is called nephrectomy. Depending on the tumor size, location and stage, the surgical oncologist may choose to remove the entire kidney (radical nephrectomy) or just the portion affected by cancer (partial nephrectomy).
Radical nephrectomy involves removal of the entire kidney. There are two types of radical nephrectomy:
Standard or "open" surgery
A four- to five-inch incision is made in the lower back. The surgeon removes the entire kidney through the incision.
Laparoscopic Radical Nephrectomy (LRN)
A small incision is made to insert a laparoscope, a thin tube with a camera that allows the surgeon to view the treatment field on a monitor. Other tiny incisions are made for miniature surgical instruments to remove the kidney. Laparoscopic radical nephrectomy (LRN) is quickly becoming the "gold standard" surgical treatment in the United States for properly selected kidney cancer patients. Its benefits include a shorter hospital stay (three days vs. one week), shorter recovery time and less blood loss than with open surgery.
In a partial nephrectomy, only the cancerous portion of the kidney is removed, along with a margin of healthy tissue. Pre-treatment imaging is used to determine what will be removed, and ultrasound is used to look for additional tumors during surgery.
As with radical nephrectomy, this procedure can be done by traditional or laparoscopic methods. Laparoscopic partial nephrectomy (LPN) is still considered developmental.
Energy Ablative Techniques
Another minimally invasive surgery technique uses either heat or cold energy to treat tumors in place, without having to remove the kidney.
Cryoablation freezes the tumor to -150 degrees Centigrade with a long, thin probe inserted into the tumor. Intensive follow-up with X-rays or other imaging procedures is required to ensure that the tumor has been destroyed. Cryoablation is ideal for smaller kidney tumors in patients considered at high risk for surgery.
Radiofrequency Ablation (RFA) is similar to cryoablation, but heat is used to kill the tumor instead of cold. RFA does have good potential for appropriate patients.
Radiation has a limited role in the treatment of kidney cancer. Kidney tumors are not very sensitive to radiation, but healthy kidneys are, so radiation as a frontline treatment is not viable.
In some cases, radiation may be used as a palliative treatment, to ease pain and other symptoms of advanced kidney cancer that has spread to bone or other areas of the body.
Chemotherapy is generally ineffective against kidney tumors, but may have a role in the treatment of metastatic tumors that have spread to the lung, bones, brain or lymph nodes. In these cases, chemotherapy would be combined with surgery or other localized therapy. A combination of gemcitabine and capecitabine to treat metastatic renal cell carcinoma has been studied in several clinical trials, and other chemotherapy agents may also be analyzed for their effectiveness in treating metastases.
A significant amount of cancer research has been devoted to immunotherapy, which uses the body's own defense mechanisms to fight cancer. All cells have protein markers, called antigens, on their surfaces that identify them as either "normal" or "foreign." The presence of foreign antigens (such as cancer cells) provokes a sophisticated chemical reaction involving lymphocytes and other cells that defend the body against disease. Some of these defender cells produce antibodies, which seek out and destroy specific antigens.
Immunotherapies are designed to manipulate the antigen/antibody immune response by targeting antigens on specific types of tumor cells. As researchers identify more of these tumor-specific antigens, they are working to develop therapeutic agents that target only those cells.
There are two basic types of immunotherapy:
Antibody therapy targets specific antigens. Rituximab and Herceptin are examples of antibody therapies currently approved for treatment of certain types of lymphoma and breast cancer, respectively.
Cancer vaccines are designed to attack antigens that exist specifically on cancer cells. However, many of these proteins are also expressed on normal cells.
Immunotherapy & Kidney Cancer
Renal cell carcinoma (RCC) is very responsive to immunotherapy, which has become the standard of care for metastatic disease. Two types of immunotherapy are used to treat metastatic RCC:
Interferon-alpha is a protein produced by white blood cells in response to a viral infection. It increases antigens on the surface of cancer cells, making them more susceptible to attack by the immune system. Interferon is an outpatient treatment administered via injection, which patients can do themselves.
Side effects of interferon therapy include flu-like symptoms (fever, muscle aches, headache and nasal congestion), depression, fatigue and nausea. Interleukin-2 (IL-2) is a protein that stimulates the growth of immune cells and activates them to destroy tumor cells. High-dose IL-2 therapy is administered intravenously, and treatment requires a five-day hospital stay. Side effects include hypotension (low blood pressure), flu-like symptoms (fever, muscle aches, headache and nasal congestion), decreased urine production, nausea and diarrhea.
Both of these therapies have only a general, non-targeted effect on the immune system, and their intense side effects are not well-tolerated by many patients. Both therapies have about a 15 percent response rate, but those who do respond do so quite dramatically.
Kidney tumors are very vascular (blood vessel-rich). They rely on a process called angiogenesis to create their own network of blood vessels, enabling the tumor to thrive and grow. These blood vessels have unique characteristics that may make them vulnerable to drugs designed specifically to target them without harming normal blood vessels.
A number of "anti-angiogenic" compounds have been developed to take advantage of the process, including bevacizumab (AvastinTM) and sorafenib (Nexavar).
These are merely examples of a growing field of treatments that target vulnerabilities specific to the tumor, with lower side effects than traditional chemotherapies or immunotherapies.
New treatments are always being tested in clinical trials and some patients with cancer may want to consider participating in one of these research studies. These studies are meant to help improve current cancer treatments or obtain information on new treatments. Talk to your doctor about the clinical trials that may be right for you.